Dustin Johnson Is Favored at a Major Again. Just Watch the Stairs.

ERIN, Wis. — Which poses the greater obstacle to Dustin Johnson’s chances of successfully defending his United States Open title: the diabolical fescue grass that frames the fairways at Erin Hills or the double-spiral staircase in his rental house?

Johnson said neither terrified him, though on Wednesday he joked, “I sit down when I go down the stairs now. I slide down on my butt.”

Considering what happened to him two months ago, that might not be the worst idea. As was the case at the Masters, Johnson came into this week as the world No. 1 and the favorite. But he never made it to the first tee at Augusta National; on the eve of the first round, he slipped down the stairs of his rental house in his stocking feet and hurt his back. He later withdrew, minutes before he was scheduled to play.

Instead of contending for his second major — and his fourth consecutive victory — Johnson was confined to the couch as the tournament went on without him.

“I watched a lot of it, unfortunately,” he said. “I just wish that I would have been playing, especially leading into the Masters I was playing the best golf that I’ve ever played.”

He added: “It’s taken me a while to get back to where I was then. I’ve still got some work to do to get back to when I was playing that good.”

In four tournaments since the Masters, Johnson has tied for second, 12th and 13th and missed a cut. Failing to advance to the weekend at the Memorial Tournament turned out to be a blessing, he said, because it freed him to spend two days practicing at Erin Hills.

“So, even though I came in late,” Johnson said, referring to this week, “I didn’t feel like I was behind the eight ball at all, because I got to prepare 10 days ago.”

This week already has been eventful for Johnson, though in a much more positive sense than before the Masters. On Monday outside Los Angeles, his fiancée, Paulina Gretzky, gave birth to the couple’s second son, River Jones Johnson. The couple already has a 2 ½-year-old boy, Tatum.

The newborn’s name, Johnson said, was Gretzky’s idea, though he provided the inspiration when he won the Los Angeles Tour stop at Riviera Country Club to supplant Jason Day at No. 1. Gretzky, he said, was turning over “Riviera” in her head and came up with River. After providing that explanation, Johnson shrugged, as if to convey that he had had little say in the matter.

Johnson, one of the longest players off the tee on a bomber’s course, is ranked No. 1 in the world and is the defending champion. Should his rivals feel intimidated this week?